We have recently shown by immunoprecipitation, peptide mapping, and in vitro translation that E1, the transforming gene region of the human adenovirus 2 (Ad2) genome, encodes two or more "families" of partially related polypeptides. One family, coded by Ela (mp 1.5-4.5) includes four 40K-50K polypeptides that are partially related; a second family coded by Elb (mp 4.5-ll), includes major 53K and 15K polypeptides that are highly related. Minor polypeptides of 14K-16K and 18K-20K were detected that are part of the 53K/15K family. Polypeptides of 28K and 11K-12K were also immunoprecipitated that are unrelated by peptide mapping to each other or to Ela-40K-50K or to Elb-53K/15K. In this proposal, we will (1) investigate whether the 28K and 11K-12K are E1-coded, by peptide mapping of polypeptides translated in vitro, (2) determine whether the E1-coded polypeptides are synthesized in 6 lines (F17, T2C4, 8617, F4, FRK, 293) of Ad-transformed cells, using radioimmunoprecipitation, O'Farrell 2D gels, and peptide mapping, (3) investigate the polypeptides specified by transformation-defective host range mutants with deletions in E1, in order to identify and map E1-coded polypeptides, and to relate specific polypeptides to the phenotypes of these mutants, (4) purify the Elb-53K and 15K polypeptides to homogeneity, attempt to purify Ela-40K-50Ks, and perhaps the minor E1-polypeptides prepare monospecific antisera, and attempt experiments to illuminate the functions of these polypeptides, (5) sequence the N-termini of the Elb-53K, Elb-15K, Ela-40-K-50Ks, and partially sequence the N-termini of cyanogen bromide fragments in order to align the structural genes for these polypeptides with the viral DNA sequence. We will also do limited analyses of E1-coded polypeptides of group A (Ad12) and group B (Ad12) and group B (Ad7) Ads, for comparative purposes with group C (Ad2, 5) Ads. Our studies may contribute to our understanding of the functions of the E1-coded polypeptides in cell transformation and virus replication, and to the organization and regulation of overlapping split genes.